No abstract

A statistical analysis shows two-way reliability of 99.98 percent or better for the WT4/WT4A system with two automatic protection channels and one manual patch channel for every 59 working channels and 20-year life expectancy for the repeaters.

The electronic circuitry and physical structure of 12 two‐phase repeaters made for use in a field evaluation test are described. The repeaters consist of four kinds of circuitry; millimeter‐wave circuits covering the 40 to 110 GHz range, IF circuits at 1.2 to 1.6 GHz, pulse circuits for the 274 Mb/sec pulse stream, and power supply circuits. All repeaters have been successfully operated over the trial repeater link in northern New Jersey. The results of this repeater development effort are the basis for an estimate of the performance obtainable in future four‐phase repeater performance. This estimate has been used in the system repeater spacing calculations.

The WT4 millimeter waveguide system requires equalization of the loss and delay of the line, which is made up of both the waveguide itself and the diplexer (waveguide channelizing filter) arrays. In the lower portion of the band (40 to 60 GHz) there is considerable linear delay (as much as 30.5 nsec per 400 MHz at 40 GHz), which is equalized by using a folded tape meander line delay equalizer. The remaining delay and amplitude deviation from the desired transfer characteristic is further reduced by field-adjustable trim equalizers. In this paper, we describe the equalization and measurement philosophy for the WT4 system and also the technologies used in achieving the resulting degree of equalization.We put special emphasis on the description of trim equalization because line equalization has been described in detail in a previous publication.1